The invention relates to a method for moving at least two elements of a placement machine in, and opposite to, a predetermined direction, in which the second element is moved by means of the first element. The invention also relates to a placement machine suitable for executing such a method.
A conventional placement machine (and its associated method) is disclosed in international patent application WO 97/38567, in which an arm forming a first element is movable in, and opposite to, a Y direction. To the arm is attached a guide forming a second element, which guide is moved along with the arm when the latter is moved in Y-direction. In this machine, the guide is also movable in another direction that extends transverse to the predetermined direction and that is denoted an X direction.
The guide comprises a component placement element by means of which a component can be picked-up from a pick-up plate and subsequently can be placed on a desired position onto the substrate. For this purpose, the arm, the guide, and the component placement element are moved in common in, or opposite to, the Y-direction and the X-direction. Near to the pick-up position and the desired position on the substrate the component pick-up element is temporarily stopped to enable it to pick-up and place the component, respectively. To enable a relatively fast pick-up and placement of components, the relatively heavy arm and the component placement element are moved as fast as possible between the pick-up position and the desired position on the substrate.
The rapid movement of the arm and the component placement element leads to relatively large acceleration and deceleration forces. As the accuracy with which a relatively light component is picked-up or moved should be relatively high, stringent requirements must be placed on the driving and guiding of the arm. This heightened accuracy requirement presents a problem that is not only found in component placement machines, but in any placement machine with which a relatively small mass is to be moved quickly and by means of a relatively large mass.